The linter gives you feedback to help you catch potential errors and keep your code in line with the published Dart Style Guide. Currently enforceable lint rules (or "lints") are catalogued here and can be configured via an analysis options file. The linter is run from within the dartanalyzercommand-line tool shipped with the Dart SDK. Assuming you have lints configured in an analysis_options.yaml file with these contents:

If a specific lint warning should be ignored, it can be flagged with a comment. For example,

// ignore: avoid_as
(pm as Person).firstName = 'Seth'

tells the dartanalyzer to ignore this instance of avoid_as warning. As lints are treated the same as errors and warnings by the analyzer, their severity can similarly be configured in an options file. For example, an analysis options file that specifies

linter:
rules:
- avoid_as
analyzer:
errors:
avoid_as: error

tells the analyzer to treat avoid_as lints as errors. For more on configuring analysis see the analysis option file docs.